package com.pkk.cloud.support.gataway.spring.filter;

import static org.springframework.web.cors.CorsConfiguration.ALL;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.cors.reactive.CorsUtils;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
import reactor.core.publisher.Mono;

/**
 * @description: 跨域解决的过滤器配置
 * @author: peikunkun
 * @create: 2019-11-09 11:52
 **/
@Configuration
public class CustomCorsFilter {


  private static final String MAX_AGE = "18000L";


  /**
   * @Description:跨域的过滤器配置
   * @Param: []
   * @return: org.springframework.web.server.WebFilter
   * @Author: peikunkun
   * @Date: 2019/11/9 0009 下午 1:27
   */
  @Bean
  public WebFilter corsFilter() {
    return (ServerWebExchange ctx, WebFilterChain chain) -> {
      ServerHttpRequest request = ctx.getRequest();
      if (!CorsUtils.isCorsRequest(request)) {
        return chain.filter(ctx);
      }
      HttpHeaders requestHeaders = request.getHeaders();
      ServerHttpResponse response = ctx.getResponse();
      HttpMethod requestMethod = requestHeaders.getAccessControlRequestMethod();
      HttpHeaders headers = response.getHeaders();
      headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, requestHeaders.getOrigin());
      headers.addAll(HttpHeaders.ACCESS_CONTROL_ALLOW_HEADERS, requestHeaders.getAccessControlRequestHeaders());
      if (requestMethod != null) {
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_METHODS, requestMethod.name());
      }
      headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS, "true");
      headers.add(HttpHeaders.ACCESS_CONTROL_EXPOSE_HEADERS, ALL);
      headers.add(HttpHeaders.ACCESS_CONTROL_MAX_AGE, MAX_AGE);
      if (request.getMethod() == HttpMethod.OPTIONS) {
        response.setStatusCode(HttpStatus.OK);
        return Mono.empty();
      }
      return chain.filter(ctx);
    };
  }

}
